Modes of Biodegradation

Supramolecular dissociation of the polyrotaxanes into constituent molecules such as a-CD and PEG was quite a new image as a mode of biodegradation in a living body. This insight was the first step to initiate our studies on polyrotaxanes as biomaterials 15 years ago [6],... 

Devinny JS, Deshusses MA, Webster TS (1998) Biofiltration for air pollution control. CRC Lewis Publishers, Boca Raton, FL, 320 pp Lee BD, Apel WA, Barnes JM, Walton MR, Barrett KB, Cook LL (1995) Biofiltration using different modes of biodegradation. In Proceedings of the 1995 conference on biofiltration. University of Southern California, Los Angeles, CA, October 1995, pp 309-316 Lee BD, Apel WA, Cook LL, Nichols KM (1996) Effect of bed medium moisture on alpha-pinene removal by biofilters. In Proceedings of the 1996 conference on biofiltration. University of Southern California, Los Angeles, CA. October 1996... 

The platform includes different decision trees for the following endpoints the estimation of Threshold of Toxicological Concern (TTC), aquatic modes of action [44], skin and eye irritation and corrosion, mutagenicity and carcinogenicity [45], in vivo micronucleus assay, identification of Michael Acceptors and biodegradation potential [46]. 

Triethanolamine is rapidly absorbed and excreted in urine (about 60%) and faeces (about 20%) mainly in the unchanged form. Biodegradation of triethanolamine to monoethanolamine or diethanolamine or to any other putative metabolite has not been shown in rodents, nor its incorporation into natural products. In spite of the search for a possible mode of bioactivation of triethanolamine, no mechanism has been reported in mammals to date. 

The TGD provides recommendations for the use of QSARs to predict long term toxicity to fish (no observed effect concentration [NOEC], 28 days) and to Daphnia (NOEC, 21 days). In particular QSARs are provided for chemicals acting by non-polar narcosis and polar narcosis mechanisms of action. No QSARs have been recommended for substances that act by more specific modes of action. For persistence, the TGD recommends two of the SRC BIOWIN models, namely the BIOWIN2 nonlinear model and the BIOWIN3 survey model for ultimate biodegradation. The exact cutoff points for these models have been calibrated on the basis of the model score for 1,2,4-trichlorobenzene — a substance that is known to be relatively persistent under environmental... 

While experimentally derived test data are preferred, where no experimental data are available, validated Quantitative Structure Activity Relationships (QSARs) for aquatic toxicity and log Kqw may be used in the classification process. Such validated QSARs may be used without modification to the agreed criteria, if restricted to chemicals for which their mode of action and applicability are well characterized. Reliable calculated toxicity and log Kow values should be valuable in the safety net context. QSARs for predicting ready biodegradation are not yet sufficiently accurate to predict rapid degradation. 

Considerations of solubility and stability have to be addressed, as well as the mode of delivery. The wide range of biodegradable polymers used for the controlled delivery of proteins and peptides include natural substances, starch. 

Chemical hydrolysis and biodegradation are the major processes involved in the transformation of naled. Volatilization from soils and/or from water is the major mode of transport for degraded naled and its bioactive degradate DDVP, as opposed to leaching to ground water. 

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